The present invention relates to a drive system and, more particularly, to a drive system for a rotary tool.
A rotary tool, such as an impact wrench, generally includes a housing supporting a motor, a drive mechanism driven by the motor, an output shaft having a first end adapted to engage a fastener and a second end adapted to engage the drive mechanism. In impact wrenches, the drive mechanism generally includes a hammer member that periodically impacts the output shaft, rotating the output shaft about a central axis to hammer or drive fasteners into or remove fasteners from a work piece.
The present invention provides a drive system, such as, for example, a drive system for a rotary tool. In one construction of the invention, the drive system includes a frame defining an axis and enclosing an interior space. The interior space houses lubricant. A piston supported by the frame is moveable axially in the interior space and is rotatable about the axis. The piston divides the interior space and defines a first chamber, a second chamber, and a plurality of channels communicating between the first chamber and the second chamber. The piston supports an inertial valve. The inertial valve is moveable between a first orientation, in which at least a portion of the inertial valve is moved away from the plurality of channels to permit lubricant flow along the plurality of channels, and a second orientation, in which the inertial valve sealingly engages the plurality of channels. The inertial valve is moveable between the first orientation and the second orientation in response to movement of the piston along the axis.
In another construction, the drive system includes a housing and a frame supported in the housing and defining an axis. The frame is rotatable about the axis and the frame defines an interior space. A piston supported by the frame is moveable axially in the interior space and is rotatable about the axis. The piston divides the interior space and defines a first chamber, a second chamber, and a plurality of channels communicating between the first chamber and the second chamber. An inertial valve is coupled to the piston. The inertial valve includes a valve stop and a spring. The inertial valve is moveable between a first orientation, in which the valve stop is spaced a distance from at least one of the plurality of channels to permit lubricant flow through the at least one of the plurality of channels, and a second orientation, in which the valve stop engages the at least one of the plurality of channels to substantially block lubricant flow through the at least one of the plurality of channels. The spring biases the valve toward the first orientation.
In still another construction, the drive system has a housing and includes a frame supported in the housing and defining an axis. The frame is rotatable about the axis and the frame defines an interior space and houses lubricant. A piston is supported by the frame and is moveable axially in the interior space between a forward position and a rearward position. The piston divides the interior space and defines a first chamber, a second chamber, and a plurality of channels communicating between the first chamber and the second chamber. An inertial valve is coupled to the piston and is moveable between a first orientation, in which at least a portion of the valve is spaced a distance from at least one of the plurality of channels to permit lubricant flow along the at least one of the plurality of channels, and a second orientation, in which the valve stop engages at least one of the plurality of channels. The inertial valve is moveable between the first orientation and the second orientation in response to movement of the piston between the forward position and the rearward position.
The present invention also provides a method of operating a drive system of a rotary tool.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.